<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<canvas id="canvas" width="400" height="300">
		不支持canvas
	</canvas>
	<script>
		var canvas = document.getElementById('canvas');
		var ctx = '';
        ctx = canvas.getContext('2d');
        ctx.rect(10, 10, 80, 80);
        ctx.fill();

        ctx.rect(100, 100, 80, 80);
        ctx.stroke();
	</script>
		
	</body>
</html>
